Medical introducer and valve assembly

Abstract

A medical catheter introducer and hemostasis valve assembly consists of a sheath having an elongated tube defining a conduit, a housing disposed at the proximal end of the sheath and further defining a conduit and an orifice, and a flexible elongated dilator sized for insertion through the hub and sheath conduit. The dilator has a tapered distal tip end and defines an axial conduit and an annular ridge having distally- and proximally-directed inclined surfaces. The sheath, when assembled with the dilator, has its distal end immediately adjacent the proximally-directed inclined surface of the ridge. A hemostasis valve for sealing the conduit is disposed in alignment with the conduit, and defines an aperture for passage of dilator and ridge therethrough in sealing engagement, into the conduit, and seals when the dilator is removed. The valve has a housing defining an orifice of a first diameter, and a valve element of a second diameter, greater than the first diameter. The valve is disposed within the orifice and is subject to externally-applied, radially directed forces that cause the valve to assume a dome-shape formation, with a convex surface disposed against the pressure of fluids within the body. As the introducer assembly is introduced into a body over a guidewire extending via a puncture opening into a vessel, the dilator and sheath flex to follow the guidewire, and the tapered end of the dilator and the distally-directed inclined surface of the ridge act to dilate the flesh about the opening to facilitate passage of the sheath. The introducer and valve may be used alone, or respectively with valves or introducers of other design. A base for attachment of the introducer to the patient is also described.

We claim: 
     
       1. A medical catheter introducer assembly including a hemostasis valve assembly comprising: an introducer sheath comprising an elongated tubular element defining an introducer conduit,   an introducer housing disposed at the proximal end of said introducer sheath and further defining an introducer conduit therethrough and an orifice,   a flexible elongated dilator sized and constructed for insertion through the conduit of said introducer housing and introducer sheath, said dilator having a tapered distal tip end portion and defining an axial dilator conduit therethrough, said dilator having an outer surface further defining an annular ridge having distally- and proximally-directed inclined surfaces,   said introducer sheath, when assembled with said dilator, having its distal end immediately adjacent the proximally-directed inclined surface of the dilator ridge, and   a hemostasis valve adapted for sealing said introducer conduit and disposed in alignment with said introducer conduit, said hemostasis valve having a wall surface defining a passageway for said dilator and said ridge therethrough wherein said wall surface defining said passageway is disposed in sealing engagement with the outer surface of said dilator, and adapted to seal when said dilator is removed,   said hemostasis valve comprising a valve housing having a valve wall surface defining an orifice of a first, smaller diameter, and a disk-form valve element of a second diameter relatively greater than said first diameter, said valve element disposed within said orifice being subjected to externally-applied, radially directed forces as result of the valve element of said greater diameter bearing on the valve wall surface of said valve housing defining said orifice of said smaller diameter, causing predetermined compression of said valve element, said valve element adapted to assume a dome-shape formation under said predetermined compression, with a convex surface disposed against the pressure of fluids from a source within the body distal of said valve element, said pressure being on the order of a few psi, wherein said disk-form valve element has a preselected thickness and diameter to allow said pressure of said body fluid against said convex domed outer surface to enhance the seal between the wall surface of said passageway and the outer surface of the dilator,   whereby, as said introducer assembly is introduced into a body over a guidewire extending via a puncture opening into a body vessel, said dilator and sheath are adapted to flex to follow said guidewire, and the tapered end portion of said dilator and the distally-directed inclined surface of said dilator ridge act to dilate the flesh about said opening to facilitate passage of said sheath therethrough.   
     
     
       2. The introducer assembly of claim 1 wherein said ridge is immediately distal of the tapered portion of said dilator. 
     
     
       3. The introducer assembly of claim 1 wherein said dilator further comprises a proximal hub, and said introducer housing and said dilator hub define cooperating means for fixedly positioning the distal end of the introducer sheath immediately adjacent the proximally-directed inclined surface of said dilator ridge. 
     
     
       4. The introducer assembly of claim 1 wherein said introducer housing defines a second conduit for passage of fluid into the conduit defined by said introducer sheath. 
     
     
       5. The introducer assembly of claim 4 wherein said second conduit is distal of said hemostasis valve. 
     
     
       6. A hemostasis valve assembly adapted for sealing a conduit connected to a vessel of the body, said valve having a wall surface defining a passageway for catheter or the like therethrough with said valve disposed thereabout wherein said wall surface defining said passageway is disposed in sealing relationship with the outer surface of said catheter or the like, and said valve adapted to seal said conduit with said catheter removed, said hemostasis valve comprising;   a valve housing having a valve wall surface defining an orifice of a first, smaller diameter, and   a disk-form valve element of a second diameter relative greater than said first diameter, said valve element disposed within said orifice being subjected to externally-applied, radially directed forces as result of the valve element of said greater diameter bearing on the portion of valve wall surface of said valve housing defining said orifice of said smaller diameter to cause predetermined compression of said valve element, said valve element adapted to assume a dome-shape formation under said predetermined compression, with a convex surface disposed against the pressure of fluids from a source within the body distal of said valve element, said pressure being on the order of a few psi, where said disk-form valve element has a preselected thickness and diameter to allow said pressure of said body fluid against said convex domed outer surface to enhance the seal between the wall surface of said passageway and the outer surface of the catheter and the like.   
     
     
       7. The assembly of claim 1 or 6 wherein said second diameter is about 10% greater than said first diameter. 
     
     
       8. The assembly of claim 1 wherein said hemostasis valve assembly further comprises a valve cup element defining an orifice and, disposed therewithin, lubricating means for lubricating a catheter or the like for encounter with the passageway of the valve, and a seal means for retaining lubricant within said introducer housing. 
     
     
       9. The assembly of claim 8 wherein said lubricating means comprises a silicone soaked sponge. 
     
     
       10. The assembly of claim 8 wherein said introducer housing and said valve cup define cooperating means for engaging opposite surfaces of said valve element for holding the valve element in position within said introducer housing. 
     
     
       11. The assembly of claim 6 wherein said hemostasis valve assembly further comprises a valve cup element defining an orifice and, disposed therewithin, lubricating means or lubricating a catheter or the like for encounter with the aperture of the valve element, and a seal means for retaining lubricant within said valve housing. 
     
     
       12. The assembly of claim 11 wherein said lubricating means comprises a silicone soaked sponge. 
     
     
       13. The assembly of claim 11 wherein said valve housing and said valve cup define cooperating means or engaging opposite surfaces of said valve element for holding the valve element in position within said valve housing.